1. Field of the Invention
This invention relates to a stereoscopic image display device that enables an observer to view a stereoscopic image using polarizing glasses.
2. Description of the Related Art
A conventional stereoscopic image display using a stereoscopic eyeglass provides a picture which can be viewed by an observer's right eye, hereinafter referred to as a “right-eye picture,” and a picture which can be viewed by an observer's left eye, hereinafter referred to as a “left-eye picture.” Such picture information is viewed through the stereoscopic eyeglass. The observer's brain then processes the left-eye and right-eye picture into a three-dimensional image.
Such stereoscopic image systems include head mounted displays and stereoscopic screen displays. In a typical head mounted display, as shown in FIG. 1, a left-eye picture display and a right-eye picture display are installed in an eyeglass frame 14, respectively.
In a typical stereoscopic screen display, as shown in FIG. 2, a left-eye picture and a right-eye picture are simultaneously or alternately displayed on a stereoscopic screen 22 of a picture display unit 20. Those pictures are then are projected onto an observer's eye through a stereoscopic eyeglass 24.
A picture display unit 20 can display left-eye and right-eye pictures using an interlace scanning system, an up and down division system, or a left and right division system. For example, one interlace scanning system displays the left-eye picture during odd-numbered scanning lines, as shown in FIG. 3A, while displaying the right-eye picture during even-numbered scanning lines, as shown in FIG. 3B. An up and down division system can display the right-eye picture on the upper half of the screen 22 and the left-eye picture on the bottom half, as shown in FIG. 4. A left and right system can display the left-eye picture on the left half of the screen 22 while displaying the right-eye picture at the right half, as shown in FIG. 5.
Systems that provide each eye with picture information can also classified into shutter glass systems and polarizing glass systems. In the shutter glass system the left-eye and right-eye pictures that are displayed on the screen are alternately selected by a shutter glass. An observer recognizes the left-eye and right-eye pictures through the shutter glass, combines them mentally, and perceives a three dimensional image.
However, the stereoscopic shutter glass system has a relatively high cost because of the shutter glass. Another disadvantage is the direct exposure of an observer to electromagnetic waves from the shutter glass. The stereoscopic polarized glass system can overcome both of these problems.
The stereoscopic polarized glass system allows the left-eye and right-eye pictures on a screen to be directed to an observer's left eye and right eye, respectively, via a polarizing glass. As shown in FIG. 6, a conventional stereoscopic display device that uses a polarizing glass system includes a patterned polarizer 26 on the picture display unit 20. The left-eye and right-eye pictures are imaged on the picture display unit in a striped or checkered display pattern. Those images pass through the polarizer 26, which is patterned the same as the display pattern. For example, FIG. 6 shows the polarizer 26 with lines of a set of first micro cells 26A and of a set of second micro cells 26B. The first set and the second micro cells have different polarizations. FIG. 7 shows first and second micro cells 26A and 26B arranged in a checkered pattern. Accordingly, the left-eye picture and the right-eye picture pass through the polarizer 26 with different polarizations. The left-eye and right-eye pictures are then applied to each eye of an observer through polarizing lens of an eyeglass, which pass only the proper component to each eye. An observer then perceives a three dimensional image.
While generally successful, the micro cell patterns 26A and 26B are usually produced from a poly organic material by fabrication processes that include at least a photoresist step, an etching step, and a stripping step. As a result, stereoscopic image display devices that use the polarizing glass system have problems in that it is difficult to obtain a high quality polarization at low cost.